It is the purpose of this project to elucidate the mechanism of the immunologic rejection of tumor grafts and to determine the mechanism of tumor suppression following immunostimulation with BCG. Current areas of investigation are: comparison of ability of endotoxin responsive (C3H/HeN) and endotoxin unresponsive (C3H/HeJ) mice to suppress tumor growth at sites of BCG infection and to reject syngeneic tumor grafts; determination of optimal conditions for immunization against transplantable syngeneic murine tumors.